4. _Such public utilities as are guarded from competition by franchises, often rise in rental with increase in population._ The leading classes of public utilities referred to are waterworks, gas-works, street-railways, ferries, and wharves. This evidently is only a special illustration of the principle just stated, where it is not easy to find a substitute for certain agents. Public franchises entitle the owners to special, sometimes exclusive, privileges, and protect them legally from competition. Not all franchises are valuable; many street-railways are unfortunate ventures, the earnings being insufficient to pay expenses, to say nothing of interest on the investment. But when they pay greatly, their high value is due to the impossibility of competition. The cars, mules, dynamos, steam-engines, and other agents combined to furnish transportation, have a special earning power because other similar agents are forbidden to be used in that market. [Sidenote: Various kinds of "unearned increments"] 5. _Industry abounds with cases of unearned increments of value due to accidental and social causes raising the rents of wealth._ The term unearned increment may be defined as an increase in rents (or value) of agents, due to something other than the efforts or merits of the owner; in fact, it is that of which we have been speaking. In some cases powerful or wealthy men can bring about social changes in entirely legitimate ways. The owner of a large factory, moving it into the country, may buy up surrounding land and found a city, converting pasture lands and corn-fields into valuable building lots. Again, social changes are produced immorally, if not illegitimately, when wealthy men or influential politicians cause laws to be passed which inure to their advantage but which may ruin many other citizens. [Sidenote: Also many chances of loss] In most cases, however, social changes are impersonally caused. The individual owner who profits by them is powerless to affect the result. He can only adapt his conduct in some measure so as to reap an advantage. He can strive to increase the number and quality and to get control of such agents as he foresees will yield higher rents. In making such a forecast there is chance of loss as well as of gain. The term "unearned increment" has been frequently used in recent years. It is often assumed to be a peculiar thing, sharply in contrast to other changes in value. The foregoing hasty review may serve to suggest how manifold and complex are the instances of it, and what an important part it plays in modern industry. DIVISION C--CAPITALIZATION AND TIME-VALUE CHAPTER 13 MONEY AS A TOOL IN EXCHANGE § I. ORIGIN OF THE USE OF MONEY [Sidenote: The consideration of money can no longer be postponed]